Multiway regenerative repeater



Dec. 21, 1943. w. T. REA

MULTIWAY REGENERATIVE REPEATER Filed Nov. 13, 1941 w R ma T NR A ET WW.. J .W y B QMIkO Ok Patented Dec. 21, 1943 UNI-rep srArfEs-i PATEN olFlFi 2,337,496A MULTIWAY REGENERATIVE 'REPEATER- Wilton T.Rea, Bayside, N. V35.', as'si'g'ribr to B ll' ".ielephoner Laboratories, Incorporated; New" York. N Y., a corporation of New YorkVVV Application November- 13, 1941', 'Serial `No; H11-81,8973" t ll'Clairns.- (Cl.'17873) This invention relates to telegraph systems and particularly to an improved multiway regenerative repeater for use in reshaping distortedisignals in telegraph systems wherein a grouptof" telegraph lines each equipped vwith an individual` repeater are interconnected through a common neutral point and in which any one of the lines so interconnected may transmit` signals which are repeated to all other lines connected to the common pointer hub of the concentration, as

it is known. The single regenerative repeater-is arranged so that it is common to the interconnected group. It receives signals transmitted by any repeater connected tol any line` forming a branch of the hub and reshapes them', beforeitheyare transmitted to the other hub branches. The v invention herein is an improvement in such a system. The improvement is designed to permit of faster operationof such a system without impairment of any of the signal elements.

An object of this invention is the improvement of telegraph systems which include regenerative repeaters.

A more particular object of this invention is the improvement of telegraphsystems in which a ,group of lines is interconnected to form branches radiating from a common point and i arrangement to prevent the possible mutilation of the iirst element of a signal transmitted by a regenerative repeater.

A further feature of this invention is an ar.- rangement in which a group of circuits are interconnected into a common hub all served by a single one-way regenerative repeater and in which regenerated signals are prevented from being transmitted back over the line which is transmitting them to the regenerative repeater.-

A further feature of this invention is an .arrangement which prevents the mutilation of the first; element of a signal train transmitted through the hub to the station which has last transmitted through the hub, when a new sta-v tion starts to transmit.

A further feature of this invention' is a fast operating releasing idevic'e"'for` a holding relay." The manner l'in'- 'which'f thefinventior' "herein" operates in'ayI be understoodY froml the following descriptionfwhen' read with' reference tothe asso-f vciated drawing which'shows'the' dropside'ofy three lines A,B, and-C'each incomingfroin individual 'inverserneutralrepeatersto' a singlel one'- Wa`y inverse neutral "regenerative repeater and associated mechanisrn's yenclosed 4within 'the 'rec"r tangle' D; Althoughfonly threelines are indi r cated "as interconnectedto one regenerativey re peatergit is to 4loe Funderstood lthat therey is ,no'f limit to v'the'nurnluerof v`lines'Which the 'single'- one-way regenerative unit will` serve.V A`

angereist-'anios with each of the linesA, B, and Care three relays. g Relays I, 2, and -3 are associated withl lineuA.;`

Relays 4. 5, and are associated linefB landi relays vl, 8 and 9 lare associated with line C. I telay y; 3 is the receiving relay for line A. It receives A trains' of signals incoming fromV themdistantfA" station `over the conductor '25; Eachftrain 'cornil prises lseven elements," iiarnelyA 'a starting element'k which is always a spacing` signal,` ve` character either marking or "spacing dependirigiponnth particular character, 'and'a lstoptelenleri'rf', whichf is always a-niarlirig Signal.' Rely3 retransmits these signals' finto' "the ll'reg'ieative"repeater'n mechanism D.

Here the signals are rege'iefatedfThat/i's to lerlgtll,l yas Originally trafllfsnl'ltted,n by an 'eletOf-" mechanicalV timing mechanism" well knowniin 'the' art.-'The'changing of thesignfalsback to their' original vlength' as .transmitted ffromn thedist'at'f" station connected Ato line A involvess'torin'gwthel received signal-"elements jin the regeneratingf mechanisrnfior a shortvinterval, equal toalooutA half vthe length of each element,- while'thenature" of eachfcharactenfor-ming element Vis definitely Y' determined-.f Then each-'element is g retransh mitted by what may be generally characterized as a motor-driven electromechanicalinterriipter which transmits 'signalelement of properA I er'igtl'i.y

The-retimed signals are then trarimsmittedsifv multaneous1y-into --lines B and-C where l they Y operate a sending relay in each line', 'relay 4 in line B and -relay -1 in line C. Thes efrelays'sirriula taneously transmit the -retimedsignalsto their associated lines. l y s Eachof the three linesfA, B and-C must lhe `connected into themregenera-tive*repeater so that signals coming in from that particular line may be retimed or regenerated. Thus lines A, B, and C are connected in parallel by means of conductors I0, II, and I2, respectively to a common conductor I3 which is extended by means of conductor I4 to the winding of relay I5, which in turn controls hold magnet I6 of the one-way regenerative. repeater unit D. The regenerative 1 repeater unit D must be connected to the respective sending relay of each of the individual groups of relays associated with each line, so that it may transmit regenerated signals to each line. Thus the sending reed I1 of the regenerative repeater, which is operated by the interrupting mechanism between its marking and spacing contacts I8 and I9 respectively is connected by means of conductor 2G to a common conductor 2l. From the common conductor 2| a sending branch, individual for each line, extends into the relay group associated with each line and through the winding of the sending relay in each group. Conductors 22, 23 and 24 are the transmitting conductors for lines' A, B, and C respectively. Each controls the sending relay for the particular line, namely relay I, 4, and 'I respectively.

One of the features incorporated into the circuit herein is an arrangement fo-r preventing the regenerated signal from being retransmitted back over the same line from which it has been received. It was explained above that the signal elements are stored in the regenerative repeater D for an interval equal to about half the length of a pulse. Then they are retransmitted to the connected lines. The sending relay of the line which is at the moment transmitting signals into the regenerative repeater for regeneration and transmission to the other lines forming the group associated with the particular regenerator is disabled in the circuit herein, so that it cannot retransmit the same signals back to the originating line after they have been regenerated. Thus, while signals are incoming over line A, the receiving relay, relay 3, associated with line A receives the signals and transmits them into the regenerative unit D. Before the regenerated signals are retransmitted from regenerator D, the sending relay, relay I, associated with line A is disabled so that it cannot transmit back to station A. The regenerated signals from the regenerative repeater D therefore operate only sending relay 4 associated with line B and sending relay 'I associated with line C.

In vorder to perform the function described in the foregoing paragraph, a relay, called a holding relay, is included in each line group. These are relays 2, 5, and 8 in line relay groups A, B, and C respectively. These relays operate to disable the associate sending relay in the group to prevent the retransmission of regenerated signals back over a line from which the original distorted signals are being received. They also function to condition the circuit so that any line in the group which has been receiving may break in and start to send. Under this condition the disabled sending relay in the relay group associated with theline which was formerly transmitting to the other lines in a group is reconditioned so that it will thereafter receive regenerated signals from the regenerative repeater and retransmit them to its associated line. y

It is particularly pointed out that, as described above, when signals are incoming from a station such as station IA, they are receivedand repeated by the receiving relay 3 into the regenerator'Dl During theinterval while this condition prevails sending relay I is prevented from operating to retransmit the signals back to station A after they have been regenerated by regenerator D.- This is performed by means of the holding relayv 2 which locks in the operated condition when the rst signal is received by relay 3 and opens the transmitting path from the regenerator which' extends through conductor 22 and the bottom'. Winding of relay I at the right-hand contact of.` relay 2. Once relay 2 operates it locks and remains locked throughout at least the interval that' signals are being received from station A. Relay 2 remains locked and relay I remains disabled until some other station in the group, such as B1 or C, which has been receiving from station A: wishes to transmit. If station B transmits, itsrelay 6 will receive. Its relay 5 will lock. Its

relay 4 will be disabled. There is one other func-- tion to be performed, however. The relays associated with line A must be conditioned so thaty signals incoming from station B will be trans-- mitted after regeneration by regenerator D tostation A. But relay I is disabled by rela-y 2 which is locked. Relay 2 is unlocked to re-enableI f relay I when relay 5 is locked in response to the.-

rst signal incoming from station B.

The time available forthe performance of this; function is short. The rst element of the first; train of signals istransmitted into the regenerator D from the contacts of relay 6 as soon as relay 6 operates. An instant later the regenerated signal is being retransmitted from regenerator D through conductors 22, 23, and 24. Dur.. ing the interval relay 4 must be disabled and relay I must be enabled. In order to enable relay I, relay 2 must be unlocked.

The invention herein includes a novel and exceedingly fast means for accomplishing this to insure the proper transmission of the first element of the rst signal train to the station which has last transmitted, when one of the stations which has been receiving starts to transmit. This feature will be explained in detail below.

The circuit of the invention is arranged also, so that in the switching apparatus employed to enable the circuit to perform the above functions, the inductive relay windings introduced into the various transmission conductors are the absolute minimum, so that distortion due to them is kept to a minimum.

DETAILED DESCRIPTION Regenerative unit The one-way regenerative unit D employed inI this circuit is well known in the art. It is de-4 scribed in detail in Patent 2,105,173, W. J. Zenner, January 11, 1938. It will be described herein only7 in so far as it is necessary to an understanding of the present invention.l

In order to condition unit D for operation, a switch 23 is operated which energizes relay 29 over an obvious circuit, operating relay 29. Relay 29 operated supplies power from source 39 to the teletypewriter motor 3| which thereafter rotates continuously. The motor driving shaft and the regenerator unit driven shaft 33 are coupled together by means of a friction clutch 32 of the well-known type. Mounted on and rigidly se-4 cured to driven shaft 33 are the three cam discs 34, 35, and 346. The driven shaft is prevented fromA rotation by means of a raised surface 31 on the periphery of stop cam34 which engages an end of the J -shaped stop arm 38, depending from and integral with armature 39, which armature,

VIf'm'agnet I6 is energizedwh n armature 39 is "ef ffeliewer el.

eiiithereiiixie ei-"eneefi eeftiiat is eonditpeed .te tritate .in ,e .limited ,ete about *it f i... l ...,l.

Vto a vixedpin U.' V"Stop argh engages raised eiiirfeeejs 31 Iiii the stop'pesitienes vindicated and retatidn of driven shaft' and the dem dises.y 314,

35, and 36', Securely 'Irieiiiited thereon, is pre- ,between its opposingco tacts lland |19.

" AAn extension of the ending reed to vthe right ef the theft ,iedere ted'lleylliiieeiie ei aniiieulatinelelemeiit .4T vfi aber 92111' e' marmer to `form a rigid'integralstrutture. yIf bar 42 is movedy upwardly, contact 4 3 on the sending 'reed will engage marking contact I8. If bar 4.2 is moved downwardly, contact 43 will engage spacing contact I9. The right-hand lend of armature 39 ris vforrr'iedfinto two yarms 44 and 45 extending one upwardly and the other dc'iv'vr'lwa'rdlyV VKCen'- tered near the upperjand lower extremity of each arm are fixed pins each securing a spring 46 and 41, each attached atitsinner end to the bar 42. AWhen the yarmature ,3S`lrrioves upwardly or down- Werdiy, the eeritreiitiiie' e -gs. 4,6 V and 4T tend to move the bar 4 2 in the s me direction to 'im- Yeert metten teseiisiire teedll! When the regenerative 'repeater is in the normal stopped position,` magnet [Gis energized and the didi/.en Shaft@ iS StQPedL .The right-hand ,end `of bei 42 ,Wili'lee leiteiiesi .irrite upper Peeitien. es k,SiiPWiiJOY .the RQetii en .the .teli am y lvlyarling contact I8 visA closed. The rst signal element in'any train of sign-al elements is alwaysa spacing" signal and theV oir- ,enereized fer this eenditiea Armature 3,9' is moved downwardly when agnet I6 is deenersized diie te tendentes. ine' 4 9 'Step .erm 38 disengages from raised "surface 31 and driven Shaft 33 rotates! .The speed efitieter .3l is fixed tien .in .en inten/.e1 .egual ,te `the .Prater time .ef

trenemiesien of O rie eemeletetainef signal elemerits- .When .reieasedermetiire #Sleeves dewnweifdly vuriiier .the ,iiiiieiiee jef 'fearing 49! Arreieetien 48 on the Aarmature .will erieefeefthe Per'iiihefry ef eem 3 5- A short ,interrati thereafter .e .Dreiec- .tion on @amate will rotate ,element .5i threlieh e rsmall arc in Va clockwisedirection about its pivot ..52 against the iitfiiierieeef entitle 5 3 'Whittie ten'- the projection on theb ttornwarrn of lever 5l and r.the lever Jwill be rotated in e .eeuiitefieleeiswie direetien byspring 5 3- .'ihe .projection en the top erm ,of lever o ftheirieht-liand end 0f .ber 4.2.1eekitietherigtithand end of the bar in its lowerpgsition. Spacineeenteet lawiliheelesed- .The bar 42 will be locked inpoeitien, .ferari istetreileeieite-ttie tell magnet I6 is de- 5l will engagethe top surfaee inent'aasetuie .length ef ,e ereeiiie ,Sieiial which will be tiene om c Neutronen-'contacting tele; Sendine'reed l l? ttieileti d" ieereed Il and' oiitthreueh"eendiieteiitlli lille theibar42 'is' still'locked'totransmit its Ygv signal," the "pulse correspondigfto 1the character forming 'signal elementv` will-be tr nsn'tted into the 'regenerativevjrepeater.` It eririarkine et epeeineii'ependirie l 4 cular character? If itis marking, et is will be energized. 1f it-isspacig 'agnet willbe'de'energized. At' the middleof .thu pulse'hvvhen themagnet doubtless willhave en properly conditioned the" rst* 'projection-ion ani v13,5 willurge follower '4.8 upwardly, raising armature ,3119, which isthus presentedto'the'mag- 'new I f the magnetiie energized-the armato? 39 will .be reta ed vin itsupper "position, "any asebar '3937x1111 remain locked initslowe p fitjiil dtiitne'nedessery interval forethe'etfe'n.- mission" 4`of a' sliartfpu'lsev ofl proper lengthfhas elapsed. Then, once more, arais'ed sii'rfacen earn 3 6 will actate' lever 5l unlatchingbar 42. vIt the"armature "39 has remained in' its upper position; springG'is tensionedl 'As soon asibar V)421s uniatched" itwill be moved uptjard; As-soon as it has completed its upward molreinent itf'ewill be relatched. When bar 42 hasVv movedupward Contact I8 will be closed". VThus a train of' signals 'of proper overall length and'eaehfofproper'iridividual 'length will be transmitted fromtlie regenerative repeater Each -signal"Av element whether marking or spacing will-*crresponjd to vfthe received Signal element.

The final signal element of a train is a marl;-

ing signal. Magnet I6 willV therefore `be energized and the armature 39 will be retained'in lits 'elevated position. When lever `5l is" latched the bar 42 will be secured in its elevated position."v

'Attention is called to thefact that the `regenerative 'repeater mechanism operating as" 'described above interposes a ixed delay of appro'irimately one half the duration of a signal element between its reception by magnet I6 and'its"re transmission by the regenerative repeater through contacts I8 and I9. This is inevitable since the Vcenter portion of each signal element is used to determine the nature of each element asthis's necessary to 1correctly determine the nature of greatly distorted signal elements, and'afterde- Ilaying until the center portion of leach'S'igrial element has been received, Va full length 'signal lelement is transmitted. Y 4 Overall circuit The operation of the overall circuit will now be described in detail. vThe condition of the vari- `ous relays when in the normal condition awaiting transmission from some line iormingpartof the group will be explained.

@heet-eet eteetreeteierfine thieueh the windings of the various relays will rst be 'explained and the relays I, 2, and 3 of line A will be used to illustrate this for lines A, B, and C. Y

Current flowing from battery throughresistance 54 and the top Winding of relay I to ground, tends to actuate the armature of relay I toward the right to engage with itsv marking contact.`

.This eiect is unopposed for the marking condition, as the circuit extending through the bottom Winding is one of the branches joined into the hub, all of which branches are terminated in lbattery of the same polarity and magnitude. The circuit through the bottom winding of relay I may be traced from negative battery through the armature and right-hand contact of relay 2, resistance 55 in parallel with condenserrSS, resistance 51, bottom Winding of relay I and conductor 22 to hub 2|. All other branches formed by lines connected into the hub through the bottom Winding of the relay in each line corresponding to relay I are arranged in the same manner. For line B the circuit extends from negative battery through the armature and right-hand contact of relay 5, resistance 58, in parallel with condenser 59, resistance 60, bottom winding of relay 4, and conductor 23 to hub 2|.

For line 4C the circuit extends from negative battery through the armature andright-hand contact of relay 8, resistance 6I, in parallel with condenser 62, resistance 63, bottom Winding, of relay 'I and conductor 24 to hub 2 I.

The sending circuit of the regenerator is joined to hub 2I in the same manner. The circuit may be traced from negative battery through resistance 64, in parallel with condenser 65, resistance 66, contacts I8 and 43, sending reed I1 and conductor 20.

No current ows in any of these branches as they are all terminated in battery of the same polarity and magnitude. Therefore the armatures of all relays such as I are maintained in engagement with their respective right-hand contacts under the influence of the current in their'respective top windings.

A circuit may be traced from ground through the top Winding of relay 3 and resistance 10 to battery. The eiect of this current tends to lmaintain the armature of relay 3 in engagement -with its right-hand or marking contact. During marking this effect is unopposed 'as no current flows through the bottom Winding of relay 3. .Conductor 25 extending to the distant station A is terminated in negative battery. 'I'he circuit (extends through conductor 25, armature and right-hand contact of relay I, bottom Winding of relay 3, resistance 61, resistance 68 in parallel with condenser 69 to negative battery. No current ows in this path while the marking condition prevails.

The circuit through the top Winding of relay 2 during marking may 4be traced from ground through the armature and right-hand or marking contact of relay 3 to the junction of parallel branches at point 1I. One of said branches extends through resistance I2 to negative battery. The other branch extends through the top winding of relay 2 to point 13 which is in effect a point on a potentiometer formedV by resistances 14 and 15 Which are terminated respectively in negative battery and ground. The valuesrof the various impedances in this circuit are such that during the marking condition, when in effect direct ground is connected to point 1I, current flows through the top winding of relay 2 in such Ya direction that its effect actuates the armature of relay 2 to engage with its right-hand contact. The circuit through the bottom winding of relay 2 is open at this time.

Corresponding relays in lines B and C are under corresponding iniiuences and their armatures are in the same conditions as explained for line A. Thearmature of relay I5 vis held in engagement With its right-hand or marking contact under the influence of Vcurrent iiowing in a circuit which may be traced from battery through resistance 16 and the bottom winding of relay `I5 to ground. No current ilows through the top winding. A circuit may be traced from battery through the armature and right-hand contact of relay I5, resistance 80 and the Winding of holding magnet I6 to ground, energizing the holding magnet and holding the armature 39 of the regenerative mechanism in the elevated position. For this condition bar 39 is locked in its upper position and contacts 43 and I8 are in i engagement.

It will now be assumed that ground is connected to conductor 25 so as to transmit a spacing signal. 'I'his energizes the bottom Winding of relay 3. 'I'he effect tends to actuate the armature of Vrelay 3 toward the left and the effect in the bottom winding is dominant over the effect in the top o1' biasing winding of relay 3, so the armature of relay 3 is actuated so as to engage with its left-hand or spacing contact. This establishes a circuit from ground through the armature and left-hand or spacing contact of relay 3, conductor I0, conductor I4, top winding of relay I5, resistance 11 and resistance 18 in parallel with condenser 19 to negative battery. The effect of current in this circuit opposes and dominates the effect of current in the bottom or biasing winding of relay I5 and the armature of Y relay I5 is actuated to the left so as to disengage ber of parallel branches extend into the variousv lines. For line B the circuit extends through conductor 23, bottom winding of relay 4, resistance .60, resistance 58 in parallel with condenser 59 and the right-hand contact and armature of.

relay 5 to negative battery'. For line C the circuit extends through conductor 24, bottom Wind ing of relay 1, resistance 63, resistance EI in parallel with condenser 62 and the right-hand4 contact and armature of relay 8 to negative bat-l tery. Relays 4 and 1 are operated simultaneouslyto connect ground to conductors 26 and 21 re-I spectively and transmit a spacing signal to sta-4 tions B and C.

In order vto prevent the transmission of a regenerated spacing signal back to station A, from which the original distorted spacing signal was received, it is necessary to open the path through conductor 22 and the bottom winding of relay I between the time that the original distorted rspacing signal is transmitted into the regenerator from the spacing contact of relay 3 and the time that the regenerated signal is transmitted back from contact I9. The path through the -bottomY Winding of relay I 'is opened in the following manner.

When the armature of relay 3 leaves its righthand contact direct ground is in eiect discon-A nested-'from point'll. Theimpedances-of the resistances-12, 14; 15' and the relay winding are such that, for this condition, the direction of the iiowv ofcurrent through the top winding of relay 2is reversed. The-armature of relay 2 is actuated to the left to engage withits left-hand contact.' A circuit may then be traced from battery through the armature and left-hand contact of relay 2, bottom winding of relay 2, resistance 8| and condenser 82 in parallel, through common holding conductor 83- and common holding resistancelillV to ground. The effect of current 'owing in this path is in a direction to hold the armature of relay 2 in engagement Withits lefthand contact and its effect is dominant over the eiiect of reversed current through the top windingofirelay 2 when direct ground is connected to'pointV llas the armature of relay 3 responds tomarking signals. The armature of relay 2 thereforeremains in engagement with its lefthand contact while signalsl are being received from station A. This maintains the path through the bottom winding of relay I open and prevents the retransmission ofsignals received from-station A back to station A.

When station A has concluded transmitting-relay'v 2- will remain locked up with its armature in engagement with its left-hand contact. Underthiscondition, when another station connected to the' hub starts to transmit, it is imperative that relay 2 be unlocked in the interval between the time of reception of the first spacing signalA element and the time when the regenerated first spacing signal element is transmitted from the regenerator. The circuit arrangements for achieving this in the present invention are unique.

Let it be assumed thatY station A has concluded transmitting. The armature of relay 2 is locked to its left-hand contact and the path' from the regenerator through the bottom winding of sending relay l for station A is open so that relay Iy is not in conditionv to, transmit regenerated signals. Station B now starts to. transmit. When the firstv or spacing signal element of the first signal train is received by relay 6., the armature of relay 6 is operated to engage with its lefthand or spacing contact. This connects the grounded armature of relay 6 through conductor I I to hub I3 and results in the regeneration of a spacing` signal in regeneratoi` D lin Ythe manner described above. The armature of relay 5 will be connected to its left-hand contact in the same manner as described for relay 2 above. A circuit may thus be traced from negative battery through the armature and left-hand or holding contact of relay 5, bottom winding of relay `5 and resistance 85 in parallel with condenser 86 through common holding conductor 8.3 and common holding resistance 84 `to ground. This circuit is connected in parallel with Athe holding circuit heretofore traced through the bottom Winding of relay 2. The magnitude of the current flowing in the holding winding of relay 2 is therefore reduced. The effect vof the reduced current in the bottom wind.- ing of relay -2 is `insuiiicientto maintain the armature of relay 2 in engagement with its left-hand Contact against the opposing effect of current in the `top winding of'relay 2 as point 1I is grounded as relay 3 is in the marking condition when cirycuit A is idle. The armature of relay 2 therefore operates toits right-'hand contact.

`When the armature of relayZ is restored to is conditioned to transmit the. regenerated signals received from station B.

All other circuits connected into the hub such. as C etc. will be in proper condition for trans.-`r

mitting. the regenerated signals as the path through thebottom windings of their relays such as 1, etc., will be closed and in condition to retion of the first signal pulse. Applicants means.

for establishing this path is designed to be especially-fast in operation. The circuit arrangement for boththe topy and bottom windings of relay..

2: and themanner in which the parallel branches through the bottom windings of relays such as2 and 5 operate to release the relay such as 2 which has been locked up since the start of transmission during the previous cycle are important aspects of applicants invention.

It is pointed out that notwithstanding relay. 2.

releasesin the manner explained when the armature of relay 5 is actuated so as to engage with its left-hand contact, the armature of relay 5 is at the same time maintained in engagement with its left-hand contact to open the path through the bottom winding ofrelay d and prevent the retransmission of the signal received from line B back to line B after regeneration.

The explanation of this is that at the time when the two holding paths through the bottom windings of relays 2 and 5 are connected in parallel, in the case of station A which is idle, relay 3 is in the marking condition and ground from the armature of relay 3 is connected to point 1|, so that the effectof the current in the top winding of relay 2 is tending toactuate the armature of relay 2 towards its right-hand contact `and after the current in the bottom winding, the effect of which is holding the armature of relay 2 in engagement with its left-hand contact, is reduced, the armature moves to its right-hand contact.' In the case of relay 5, its armature is operated to the left when the armature of relay Ii brealgs from its right-hand contact, disconnecting ground from point 81. 'I 'hat is to say. for the -first spacing condition of relay 6, the eiect'of the current in the tcp winding of relay 5 actuates the armature of relay 5 to the left. After the armature of relay 5 engages its left-hand contact the effect of the current in the bottom or holding winding of relay 5 augments the effect of the current yin the topwinding `and both windings are operating to hold the armature of relay 5 to the .left during the reception of the rst spacing signal by relay 5. It is emphasized that in the case of relay 2, because relay 3 is on marking while not transmitting, the effects of the currents in the two windings of relay 2 are opposed -when .the first spacing signal element is received by relay 6 and the holding effect in the bottom lwinding of relay 2, is reduced, by the parallel branch through the bottom winding of `relay 5, suificiently to permit the armature of relay 2 to vbe actuated toward the right. As soon as the .armature of relay A 2 leaves its left-hand contact, the current through the bottom winding of .relay ;5 rises to its full value as the parallel '.branchthrcugh the bottom winding of relay 2 withstanding the reversals inthe direction'of current iiow through it stop Winding, asfground is alternately connected to and disconnected from marking and spacing signals from line B.'

point Blas the armature of relays 'respondsfto The purpose of the condenser such" as` 82` in` each of the parallel holding branches is to'develop a transient which forces thelmagnitude of the current in the bottom winding of'a holding relay quickly to a value considerably below "its steady state value? when two holding Vcircuitsl through the bottom Windings'such as 2 and 5 are interconnected'. 'This'increases the speed withv which the holding relay such asV relay 2 will re-- lease and reestablish' the" transmitting path through the bottom windingv of a sending relay such as relay I when 'a 'station suchtas2 B starts' to transmitV Vfollowing transmission Yby 'a station such as/A.

1. In a telegraph communiatibn-circuit, a, piu.` rality of telegraph lines interconnected through individual repeaters to'a single 'one-way regenf erative repeater V'cmrnonto' all "of" said "lines,

means in'said 'circuit' for regenerating-'signals inthat each of 'their transmitting circuits is'closedV before the first` regenerated signal' element is transmittedV saidY means including ra' holding circuit comprising parallelbranches in a plurality of whichj the magnitude of 'the holding current is reduceds'imulta'neously to 'a `current of lower value to eiect the'closing of one of said trans: mitting circuits:v4`

2. As elements in a multiway regenerative tele; graph repeater circuit,'"individual'pol-ar relays each having an armatureV connected in series in" individual Ycommunication branches; -said branchesconnected to the output of a single-oneway regenerative rrepeater' arranged to serve all of said branches in common, said relaysincluding means kfor holding one of said branches continuously open whensig-nals are not to be transmitted therethroughtwo independent windingson each of said relays, and means for transmitting current in*V reverse directions through oneY of said windings and current of two different magnitudes through -theother of said windings.

l .3. In a telegraph system, at .leastthreeteler ,which currentsio'f two different magnitudes are passed at different times to control Vthe effective connection 'of oneY of said individual repeaters to theoutput of said regenerative repeater.

4. l n a multiway regenerative telegraph re# Qpeater system. receiving branches fromV individual repeaters connected in'parallel to the inputof a single regenerative repeater arrangd to serve all is opened. Therefore, v'the armature of relay 5" will remain locked to its lefthand contact,not'f of said Vrepeaters in common, transmitting branches to individual repeatersv connected in4 parallel to the output of said regenerative repeater and arepeater transmission enabling cir- 5' cuit having a group of parallel branches each of which is connected in parallel to a winding on a polar relay in one of said individual repeaters.

5. In a telegraph repeater, a relay, a winding thereon, means connected to said windingefor transmitting a rst steady state current ofA a rst magnitude in a first direction through said winding at a first time to operate an armature of said relay to a particular position, means connected to said windingfor transmitting a second steady state current of a second and lower magnitude than said first magnitude through said winding in the same direction as said first direction at a second time and means connected to said winding for developing a transient voltage to reduce the magnitude of said second current below its steady state value to permit the position of said armature to be reversed faster.

6. In a telegraph system, at least three telegraph relay repeaters interconnected through av single one-way regenerative repeater, means in said system for receiving signals from any one of said relay repeaters and repeating regenerated' signals from said regenerativeV repeater to allothers of said relay repeaters anda winding of not'more than one relay in the circuit connecting Vthe output of said'regenerative repeater and the transmission conductor directly connecting each relay repeater with the distant terminal.

7. A multiway regenerative telegraph repeater system', at least three'telegraph'lines therein extending individuallyA from acommon -regeneratjing station to three distant stations, an-individual telegraphrelay repeater connected to each line at said regenerating station, a regenerative 40 repeater having an input and an output at said regenerating station, meansin said system, for impressing telegraph signals receivedfrom any of said linesthroughitssaid individual, relay re-V peater on said input, means for impressing regenerated telegraph signals kfrom said ,output on all others of said lines simultaneously through its, said individual repeater in response thereto, said latter means. comprising individual branches o a parallel transmittingcircuit interconnecting said output and each of said lines,' and a winding of not more than 'one relay connected between the output ofV said regenerator and each of the conductors connected directly to the distant station.

8.V A multiway regenerative vtelegraph repeater 1system comprising a single one-way regenerative repeater interconnected by means of individual line repeaters to' at least three telegraph conductors each extending to a distant station, means in vsaid system for' regenerating telegraph signals received from any one of said conductors and impressing them simultaneously on all of the others of said conductors, and a winding of one relay only interposed in the complete circuit branch connecting the output of said regenerative repeater to'each of said conductors.

9. In a multiway regenerative telegraph re peater system, a group of at least three individual telegraph line repeaters connected to 'a single one-way regenerative repeater, means in said system for receiving signals from any one of said line repeaters and repeating regenerated signals in response thereto to al1 of the others of said line repeaters simultaneously, a polar control relay in 'each of said line repeatersfor preventing the transmission of regenerated signals back to the same line from which corresponding distorted signals are received, a transmitting branch connecting the output of said regenerative repeater to each of said line repeaters, said branches being connected in parallel, a winding on a transmitting relay and an armature on said polar control relay both connected in series in each of said branches, a locking circuit on each of said polar relays, and means directly connected to said locking circuit for increasing the speed of the unlocking operation.

10. In a telegraph system, a polar relay, a rst winding, a second Winding and an armature, all on said relay, means for passing current of a rst magnitude through said rst Winding and for passing no current through said second Winding at a first time to actuate said armature to a first position, means for changing the direction of said current in said first Winding While maintaining no current in said second Winding to actuate said armature to a second position at a second time, means for passing a locking current through said second Winding to lock said amature in said second position at a third time, means for intermittently reversing the direction of the current in said first Winding, means for maintaining said armature in said second position notwithstanding said reversal at a fourth time, and meansl comprising the connection of a circuit in parallel with said second Winding to reduce the magnitude of said locking current in said second winding and permit the restoration of said armature to its rst position in response to a reversal of the direction of current in said first Winding at a fifth time.

11. In a multiway regenerative telegraph repeater system, at least three lines each extending to a distant station and each equipped with an individual repeater all connected to a single one-way regenerative repeater mechanism, means for receiving distorted signals from any one of said lines and repeating regenerated signals to al1 of the other simultaneously in response thereto, and not more than one relay Winding interposed between the output of said regenerative repeater and any of said lines.

WILTON T. REA. 

